scholarly journals Characterization of Potential Micrometeorites by Synchrotron Analysis

Geosciences ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 275
Author(s):  
Madison Esposito ◽  
Kevin Souhrada ◽  
Erin Garland ◽  
Mary Kroll ◽  
Robert Bolen ◽  
...  
Keyword(s):  
High School Students ◽  
Small Particles ◽  
School Students ◽  
Edge Structure ◽  
X Ray ◽  
Three Samples ◽  
Iron Nickel ◽  
X Ray Absorption ◽  
Extraterrestrial Material

Micrometeorites (MMs) are small particles that account for most of the extraterrestrial material deposited on Earth. Synchrotron X-ray fluorescence and diffraction allowed for chemical and mineral characterization to distinguish MM from atmospheric particulate. The relative components of iron, nickel, and other elements were considered in the identification of ferrous MM while high amounts of titanium were considered an indication that the particles were of atmospheric origin. Out of 100 samples collected by high school students and teachers, eight were taken to a synchrotron for analysis. Of those eight, three exhibited extraterrestrial compositions. X-ray absorption near-edge structure analysis revealed that the same three samples contained sulfide, the main sulfur form constituent in MM. X-ray microdiffraction analysis showed the presence of the minerals pentlandite and forsterite. Collectively, these results support the extraterrestrial nature of the three particles.

scholarly journals Database of ab initio L-edge X-ray absorption near edge structure

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yiming Chen ◽  
Chi Chen ◽  
Chen Zheng ◽  
Shyam Dwaraknath ◽  
Matthew K. Horton ◽  
...  
Keyword(s):  
High Throughput ◽  
Scattering Theory ◽  
Research Community ◽  
Metal Compounds ◽  
Edge Structure ◽  
X Ray ◽  
Initial Release ◽  
Computational Workflow ◽  
X Ray Absorption

AbstractThe L-edge X-ray Absorption Near Edge Structure (XANES) is widely used in the characterization of transition metal compounds. Here, we report the development of a database of computed L-edge XANES using the multiple scattering theory-based FEFF9 code. The initial release of the database contains more than 140,000 L-edge spectra for more than 22,000 structures generated using a high-throughput computational workflow. The data is disseminated through the Materials Project and addresses a critical need for L-edge XANES spectra among the research community.

Characterization of As-doped, p-type ZnO by x-ray absorption near-edge structure spectroscopy: Theory

2006 ◽  
Vol 89 (22) ◽  
pp. 222113 ◽  
Author(s):  
Sukit Limpijumnong ◽  
M. F. Smith ◽  
S. B. Zhang
Keyword(s):  
Edge Structure ◽  
X Ray ◽  
P Type ◽  
X Ray Absorption

The Structural Characterization of a Series of Uranium-containing Gadolinium Zirconates

2012 ◽  
Vol 1475 ◽  
Author(s):  
Daniel J. Gregg ◽  
Yingjie Zhang ◽  
Zhaoming Zhang ◽  
Inna Karatchevtseva ◽  
Mark G. Blackford ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Diffuse Reflectance ◽  
Charge Balance ◽  
X Ray Diffraction ◽  
Edge Structure ◽  
Gadolinium Zirconate ◽  
X Ray ◽  
Host Materials ◽  
X Ray Absorption

ABSTRACTA series of uranium-containing gadolinium zirconate samples have been fabricated at 1723 K in air. X-ray diffraction and Raman spectroscopy have confirmed pyrochlore or defect fluorite structures, while diffuse reflectance, X-ray absorption near edge structure and X-ray photoelectron spectroscopies indicate a predominantly U6+ oxidation state, even when Ca2+ was added to charge balance for U4+. The results demonstrate the potential of gadolinium zirconates as host materials for actinides.

Characterization of As-doped, p-type ZnO by x-ray absorption near-edge structure spectroscopy

2006 ◽  
Vol 88 (11) ◽  
pp. 112103 ◽  
Author(s):  
Veeramuthu Vaithianathan ◽  
Byung-Teak Lee ◽  
Chang-Hwan Chang ◽  
Kandasami Asokan ◽  
Sang Sub Kim
Keyword(s):  
Edge Structure ◽  
X Ray ◽  
P Type ◽  
X Ray Absorption

Fluorescence Yield Xanes and Exafs Experiments: Application to Highly Dilute and Surface Samples

1993 ◽  
Vol 37 ◽  
pp. 607-617 ◽  
Author(s):  
Glenn A. Waychunas ◽  
Gordon E. Brown
Keyword(s):  
Bound State ◽  
Fluorescence Yield ◽  
Interatomic Distances ◽  
Edge Structure ◽  
X Ray ◽  
Surface Samples ◽  
Radiation Sources ◽  
To Come ◽  
X Ray Absorption

The development of intense synchrotron radiation sources during the last twenty years has enabled several types of x-ray spectroscopy and scattering techniques to come into practical use. One of the most significant methods for the characterization of extremely dilute samples is high resolution x-ray absorption-edge spectroscopy. The technique is usually divided into two separate methods according to whether the x-ray absorption near edge structure (XANES) or the extended x-ray absorption fine structure (EXAFS) is analyzed. XANES features are due mainly to bound-state electronic transitions just below, and on the low energy side of the edge, and to multiple scattering resonances on the top of the edge and at somewhat higher energies. EXAFS features are oscillations due to ejected photoelectron back scattering interference processes in the close vicinity of the absorber atom. XANES analysis is used to determine atom valence, atom site distortion from regular geometries, and other details of the atom site. EXAFS features can be analyzed to recover interatomic distances between the absorber atom and its first few shells of neighbors, as well as the number and types of these neighbors. Together these techniques can provide an atomspecific probe of die short-range structure within almost any type of condensed matter.

Raman and X-ray absorption near-edge structure characterization of GaN implanted with O, Ar, Xe, Te and Au

2007 ◽  
Vol 29 (12) ◽  
pp. 1856-1860 ◽  
Author(s):  
M. Katsikini ◽  
J. Arvanitidis ◽  
E.C. Paloura ◽  
S. Ves ◽  
E. Wendler ◽  
...  
Keyword(s):  
Structure Characterization ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

Characterization of CeO2–Al2O3–SiO2 glasses by infrared and x-ray absorption near edge structure spectroscopies

1996 ◽  
Vol 11 (10) ◽  
pp. 2641-2650 ◽  
Author(s):  
Sin-Lung Lin ◽  
Chii-Shyang Hwang ◽  
Jyh-Fu Lee
Keyword(s):  
High Frequency ◽  
Structural Characteristics ◽  
Edge Structure ◽  
Network Modifier ◽  
X Ray ◽  
Reflection Data ◽  
Aluminosilicate Glasses ◽  
Ir Reflection ◽  
X Ray Absorption

Structural characteristics of CeO2–Al2O3–SiO2 glasses have been studied by infrared and x-ray absorption near edge structure (XANES) spectroscopies, and the Kramers-Kronig analysis of IR reflection data was performed. Results of IR spectra show that ceria is the network modifier and favors the formation of [SiO4] tetrahedron with nonbridging oxygens. The high frequency Si–O–Si stretching vibrational peak near 1100 cm−1 shifts toward the lower frequency as ceria content increases and alumina content is constant. XANES data of the cerium LIII edge show that the majority of cerium ions in cerium aluminosilicate glasses are Ce3+ ions. The ratio of Ce4+/Ce3+ increases with increasing the ratio of Ce/(Al + Si). However, the ratio of Ce4+/Ce3+ decreases with increasing the ratio of Al/(Al + Si).

Sign in / Sign up

Export Citation Format

Share Document